Distributor means for pulverized fuel burners



Oct. 28, 1952 J. J. RAGUSAN 2,

DISTRIBUTOR MEANS FOR PULVERIZED FUEL BURNERS Filed June 28, 1949 2SHEETSSHEET l INVENTOR James J. Rugusun Oct. 28, 1952 J. J. RAGUSAN2,615,407

I DISTRIBUTOR MEANS FOR PULVERIZED FUEL BURNERS Filed Juhe 28, 1949 2Sl-IEETS-SHEET 2 71111111111111; II/111111111114 A INVENTOR il mes J.Ruguson ATTO EY Patented Oct. 28, 1952 DISTRIBUTOR MEANS FOR PuLv mzEnFUEL BURNERS James J. Ragusan, Brooklyn, N. Y., assignor to CombustionEngineering-Superheater, Inc., New York, N. Y., a corporation ofDelaware Application June 28, 1949, Serial No. 101.756

.1 a This invention relates to pulverized fuel burners and particularlyto improved means for uniformly distributing finely ground coal and thelike into and from such burners, especially when same are horizontallydisposed.

In horizontally disposed pulverized fuel burn-- ers the fuel and airmixture is given a rotative movement in passing through the burnerbecause of a volute or tangential entrance into the fuel nozzle andspiral rifiing in the latter. The rotative movement'imparted to the fueland air mixture produces turbulence and a centrifugal force which causesit to fan out or spread into a flame cone upon its entrance into thefurnace. Seenthrough an observation door in the furnace wall oppositethe burner, the flame from a well designed and properly operated burnerof the type here considered appears to radiate from the burner centerand form a uniform and annular disc.

Even distribution of fuel and air to a furnace with a horizontallydisposed burner is more difficult than with burners disposed verticallyand firing downwardly into the furnace. Ordinarily there are fewerburners and therefore the streams of fuel entering the furnace arelargerr;

the path of the burning mixture between the tip of the burner and thegenerating bank also is usually shorter than with vertical firing.Consequently, the distribution of coal and air over the entire crosssection of the moving stream of burning mixture from the burner wall tothe generating bank must be accomplished in a short' distance from theburners and the distribution must be uniform throughout this section. Ifthe distribution is not uniform, certain parts of the furnace get toomuch fuel and too little air and other parts get too much air and toolittle fuel. It will readily be seen that the more the flame fans outfrom the central burner axis the shorter the distance from the burner inwhich the fuel and air can be spread uniformly across the entire crosssection of the furnace. To make fanning out of the flame effective, itis necessary that thev pulverized coal (or other fuel) should beuniformly distributed around the periphery of the tip of the fuel nozzleand this isa most diflicult problem to solve because it is affected notonly by burner design but by the shape and arrangement of the fuelpiping.

Feeding the coal and primary air mixture to the volute. or tangentialentrance of a horizontally disposed burner and the rifling thereinimparts a rotative movement to the coal and air mixture causing the coalto'be concentrated 2 Claims. (01. 110-104) along the inner wall of thenozzle so that it is discharged from the "nozzle tip' in an annularring. Some segments of this ring may contain more coal than othersbecause bends in the pipingto-the burner and the direction of approachof thepiping with respect to the burner inlet may cause the coal andair'mixture tobe introduced to the inlet at one side or the other of thelatter 'sothat some segments of the an-' nular ring at the nozzle tipreceive less coal than others. Consequently, when the coal in thesesegments is discharged approximately radially into the: furnace, certainparts of the furnace get too much'fuel and too little air while otherparts get too much air and too little fuel.

An objectof this invention'is' toprov'ide'animproved means in the inletto the'bu'rner nozzle which will cooperate with the burner to produce auniform distribution of fuel at the tip of the latter so as to effect amore eflicient combustion:

of the fuel and use of the associated furnace.

One illustrative embodiment of the inve'ntic'n'r is' shown by "the:accompanying drawings where in: a I

Figure 1 is 'a sectional elevation, taken on line i--l of Fig. 5; of ahorizontally disposed fuel burner for introducing fuel into a furnace;

Figure 2 is an enlarged sectional view on theline 2'2 in Figure 1showing the new adjustable deflecting means in the volute entrance tothe fuel burner for directing the-fuel stream so as to cause the fuel tobe introduced to the inlet of the burner nozzle uniformly thereby attaining a uniform discharge of the fuel and air mixture from the tip of theburner nozzle;

Figure 3 is a sectional view on the line"3-3 in Figure 2 illustratingthe manner of introduc tion and controlling of the fuel stream at'theinlet of the burner nozzle to effect uniform dis charge from theburner-nozzle tip;

Figure 4 is a sectional'viewon the line 4-4 in Fig. 1 with the. adjacentpart of the cylindrical. inlet portion of the burner nozzledeveloped-into: a plane represented by dotted line A as indicated.

in Fig. 2;

Figure 5 is a plan view of the burner shownin Fig. 1 with diagrammaticillustrations of several angular positions for the fuel pipe inapproaching a bend therein leading to the burner and with showings ofthe consequent effect uponthefiow' and distribution of the fuel producedby the bend in the piping;

Figures 5a, 5b,-5c, 5d and 5e are sectional views similar to a sectionalview taken at line 4 4,

Fig. 1 Showing" the distribution of thecoal with coal from the burnertip resulting from. a non-.

uniform feeding of the coal across the inlet to the burner nozzle;

Figure8 is an enlarged side view of one of the new adjustable deflectingvanes;- and Figure 9 is an enlarged front view of the sameadjustabledeflecting vane.

Typical burner to be benefitted" In Fig. l the numeral I2 designates avertical wall of a furnace having an opening [4- thereininto which thetip of a horizontally disposed fuel burner nozzle designatedas a wholeby the numeral .l 6 extends. for introducing. fuel and. airinto. the.furnace. through an. air duct l-8 supplying secondary air fol-thecombustionof. the fuelaround the. tip 20.

Qfthe. burner nozzle "5.. Thev burner nozzle l6 has. al volute entrancesection 22 (as. shown in.

Fig.2) to which the fuel andair mixture is suppliedthroughthe fuel pipe24' having a bend.26.

therein near the burner. Pipe 24. may approach theburnernozzle Iii-fromvarious positions, such as those designated by the reference letters a,b, c, d, andev in Fig. 5. I

T-hefuelpipe. 24 maybe cylindrical as shown.

whilenear the: entrance portion 28 ofthe burner the crosssectionthereofisrectangular'so that. itghas aflatvolute.undersurfacetfl (seeFig; 2)

extending; parallel to the burner axisfor the widthof the entrance 2B.-The-interior: wall of- I the; cylindrical burner nozzle I 6isprovidedwith aplurality of helical ribs. 32 extending'from. ad.-jacent tip rearwardlythroughout nearlythe length; of ithez-burnernozzle. Ribs 32 terminate short of theouter end'wall 34 of the burnernozzle,

and progressing clockwise around the burner nozzlethe end of eachsuccessive helical. rib extends furtherv across the: inlet opening 36(see. Fig. 4) than its predecessor which is nearer. said,

inlet opening.

Goal-leaving'the; inlet SE of, the: burnerin a uniform ribbonindicated-by thedots-B (see Fig. i): onxthepflat, bottomsurface of the.volute'2-2 flows; into the: burner-nozzle and encounteringsuccessivehelical ribs, 32 is sheared off or diverted andif, onleaving the:volute-section 220i burner nozzle I6, thecoalis distributed uniformlyacross the' inlet- -36 onthe. fiatsurface 30 and before encountering.successive helical ribs; 32 it will be uniformly discharged into thefurnace as indicated in Fig. 6.

- The problenrto be sol'uecl' Howevcnif; some; sectorsv of. the: ringof. coalat.

The. burner nozzle. l6. projects.

The different segments of.

the nozzle tip contain more coal than others, the adjacent part of thefurnace receives more coal than parts of the furnace opposite thesectors having the smaller amounts of coal; such lackof uniformdistribution being indicated in Fig. 7. For example, if the section ofthe fuel supply pipe ahead of bend 26 approaches the burner in apositionin front thereof as indicated at c in Fig. 5, the coal in passin aroundthe bend 26 concentrates against the outer wall thereof as indicated bythev dots. In passing around the bend v thecoal enters inlet 28concentrated against the opposite wall of the pipe and upon reaching theburner nozzle. the; coal is concentrated against thesidewall' 38 cf thevolute section 22 at the w coal being thrown against therouterwallinnthe fuel pipe in. passing around: the bend-:when the pipexapproaches.the burner nozzle; from a posttion infront but to one-sidev thereof; asindicated; at'b and'dinFig. 5i

As contrasted with .such; uneven distribution.

of; fuel. at the inletofrthe; burner.- nozzle, Fig-.52."

shows: the distributionatgtheinlet whenthezco'ala in passing around thebend. concentrates-againsttheouter wall of: the .fuel pipe,apprcachi'ng'from. the left oftheburner nozzl'einFig. 5, and 11111355?ingaround the bend reaches: the position: shown.- inFig. 5 where-it: isuniformly distributed: across the inlet-.to the-burner:-nozzleand thusequal; amounts of fuel will) bevsheared off. by successive helical ribs32 that it encounters; as a result." each; of 'thesegmentalribbons-ofcoal travelling spirally to the tip 20. of: the burnervnozz'ler containsequali amounts'and therefore the annular: ring: of coalat the burnernozzle tip has substantially equal. amounts of' coal in its differentsegments. Thus; substantially uniform amounts of coal are dis? charged"all around the tip: 29 as indicated in Fig. 6. I When the fuel feed pipe24 comes in:from the right hand side of the burner a-s-shown. by theposition a in Fig. 5', the fuel"concentratingonthe outer'side of thebend after passingthe latter will reach the inlet concentrated againstthe-topwall lll-ofthe'outletas indicated'in Fig. Swand Fig. Z but willpass across the outlet-opening'36 and thus flow towards the spiral ribs"32" in the-: same manner as when forming a ribbon on the flatbottom 30of the inlet to the burner'nozzle.

However, it is not always possible to locate the fuel piping so that itapproaches the burner from a position which produces a uniformdistribution in a ribbon across the'inlet of the burnennozzlee In manyinstallations it necessary to installthe outlined: above.

F'ueZ distributor means ofthisinoentiorr.

To overcome suchuneven distributionand-deelivery of fuelto the.-inlet-port: 36 of thebu-rner.

nozzle lt when the fuel pipev is installedinsucht.

unfavorable positions the preferred. embodiment of my invention. here.illustrated provides. a. series.

of. individually adjustable, deflecting; vanesAZ. can;

pable of intercepting a stream of coal passing along the wall 38 (seeFigs. '1and'3 of the volute inlet section 22 andconverting anincomingflow of suchmaterial that is non-uniformly distributed along the axialdimension of the volute inlets outer peripheral wall 30 into a flowbeyond the vanes which issubstantiallyuniform at its point of entranceinto the spaces 44 formed by helical ribs 32.

To accomplish this each of vanes 42 is individually and rotatablymounted on the flat peripheral "surface 30 f'the" v01ute inlet 22 in anysuitable manner as by"means of a threaded shankAS and a securing nut48;; Each vane can beadjust'ed angularly to the direction of flow of thematerial by imparting turning movement thereto through a slot 50 in theouter end of threaded shank 45. This slot is cut parallel to vane 42 soas to indicate the angular position of such vane.

Adjustment is made to each vane 42 individually depending on variableposition of fuel pipe 24 (as shown on Fig. a, b, c, d and e) and asindicated by shape of flame observed through observation door of furnaceunder actual operat-.

ing conditions until this flame attains the form of an annular rounddisk resulting from a uniform emission of the pulverized coal around theperiphery of the nozzle tip substantially in the manner shown in Fig. 6.

While the adjustable deflector vanes 42 of my invention are particularlyapplicable to fuel supply systems having horizontally disposed burners,they may also be utilized to angularly displace the coal stream withrespect to its direction of flow when entering a vertically disposedburner or when entering burners for tangential firing so that a uniformdistribution of coal across the burner is efiected.

Invention successfully solves problem .The high practical utility of thenew fuel distributor means .herein disclosed has been convincinglyconfirmed by successful operating results obtained in actualinstallation of the improvement on pulverized fuel burners of the typeillustrated herein.

Experimental test installations initially made have proven sosatisfactory that the improvement is expected to go into widespreadcommercial use in, and be made a standard part of, future installationswhich call for a correction in the distribution of pulverized fuel thatis supplied to burners such as are here illustrated.

Prior to this improvement no uniformly successful expedient for solvingthe problem stated had been available; all earlier-proposed methods ofsolution proving far less effective than the present one and in certaincases aggravating rather than minimizing the difficulty.

But by use of the present improvement it now becomes possible to correctthe most stubborn situations and to do this simply, reliably andcheaply; proof as to the practical success of such correction beingbased on actual operating experience (as earlier mentioned) rather thanmere theory alone.

Although I have illustrated and described but one preferred embodimentof the invention, it will be recognized that changes in the constructionmay be made without departing from the spirit of the invention asdefined by the appended claims.

Having thus fully described my invention what I claim as new and desireto secure by Letters Patent is:

1. In "a pulverized fuel burner the combination of-a burner nozzle'ofgenerally circular cross section and having an inlet end and an openoutlet adapted to communicate with a combustion chamber; tangential fuelfeed means including an inlet port in the peripheral wall of said burnernozzle disposed to introduce the fuel suspended in primary airtransversely into the nozzle inlet end; said-tangential fuel-feed meansalso including 'a. fuel guiding section having an inner volute surfacewhich tangentially adjoins both the periphan inner surface of saidburner nozzle and said tangentialfuel feed means; a plurality ofiridividual deflecting vanes disposed in a longitudinal I row in "spacedrelation across the said burner nozzles inner peripheral surface thattangentially adjoins said tangential fuel feed means; a plurality ofhelical ribs disposed on the inner surface of said peripheral burnernozzle wall causin said suspended fuel to advance helically in aperipheral layer to the outlet of said burner nozzle, said helical ribscommencing at points located at distances from said longitudinal row ofdeflecting vanes which progressively increase in a circumferentialdirection along said burner nozzles inner peripherical surface, the ribnearest said inlet port in the direction of material flow terminatingadjacent the nozzle side of the inlet port and successive ribs about thewall of said nozzle in direction of material flow extendingprogressively further across said inlet port; each of the aforesaiddeflecting vanes being pivoted about a vane axis which is substantiallynormal to the peripheral inner surface of the aforesaid burner nozzleand each vane having two wings oppositely and radially disposed withrespect to said vane axis; and individual adjusting means forpositioning said vanes angularly to the direction of pulverized fuelflow therepast through said tangential fuel feed means whereby thesedeflecting vanes may be set so as to convert an incoming flow ofpulverized fuel that is non-uniformly distributed across said peripheralinlet port into a flow beyond the deflecting vanes which issubstantially uniform at its point of entrance between the aforesaidhelical ribs.

2. In a pulverized fuel burner, the combination of a burner nozzle ofgenerally circular cross section and having an open outlet adapted tocommunicate with a combustion chamber; an inlet passage for said burnernozzle including an inlet port in the peripheral wall of the nozzleremote from the said open outlet end and adapted to supply said burnernozzle in a direction tangential to the inner surface thereof with astream of pulverized fuel suspended in primary air; said passage alsoincludin a fuel guiding section having an inner volute surface whichtangentially adjoins the inner peripheral wall surface of said burnernozzle; a plurality of helical ribs disposed on the inner surface ofsaid peripheral burner nozzle wall forming a plurality of helicalchannels and causing said suspended fuel to advance helically in aperipheral layer substantially within said channels to the outlet ofsaid burner nozzle, the inlets to said channels being spaced uniformlyin the direction of said nozzles axis across the width of said inletport but placed at a distance which progressively increases therefrom inthe direction of pulverized fuel flow; a plurality of individualdeflecting vanes spacedly disposed on said burner nozzles innerperipheral surface that tangentially adjoins said inlet passage in adirection substantially-parallel to the axis of said nozzle and adjacentthe aforesaid peripheral inlet: port. but intermediate theentrance:tosa-id. helical channels and said port so that; each: deflecting; vaneoccupies a portion of.

saidperiphera-l inlet port, each vanebeing pivoted about avaneaxis whichis substantially normal to. the peripheral inner. surfaces of theaforesaid burner nozzle: and eachvane having two wings oppositely andradially disposed with respectyto said vane. axis; and individualadjusting means for; positioning, saidv vanes angularlyto. thedirectioniof. pulverized fuel flow therepast through said peripheral inlet wherebythese deflecting. vanes may, beset so-as to convert. an incoming flow ofpulverized fuel that is non-uniformly. distributedacross-said'peripheralinletportinto a 15 4- fiow. beyond. thedeflecting, vanes which; is sub? stantially uniform at its: point. of.entrance mm the aforesaid: helicalv channels... v J

, JAMES -J; RAGUSAISI.

. REFERENCES. or rED:

The following-references; are of' recordfin' the.

file'ofitl'iis pa/tent: UNITED STATES PATENTS Number. Name. Date;

2,320,57 5 Dunn June.1,,1943 2,325,318 Hendrix. J uly 27,..1943;2,325,442 Vroom" July-'27,v 1-943,

